USE OF BLUE LAKE AS AN INDICATOR OF BACTERIAL PENETRATION INTO EGGS

Blue Lake, an insoluble dye, was evaluated as an indicator of potential bacterial penetration into eggs. Various groups of eggs (fresh-laid; commercial; water-washed) were dipped in 0.25% (w/v) Blue Lake in 0.1% Triton X-100 solution for 2 min and incubated at room temperature up to 1 ± 24 h. Penetration was detected by counting the blue dots on shell membranes after breaking the eggs. Commercial eggs allowed the easiest penetration. All commercial eggs showed blue dots even at 2 min incubation and the average count reached 111/egg at 1 h. Water-washed eggs allowed much less penetration than commercial eggs and the counts of blue dots on those eggs were 10/egg at 2 min and 22 at 1 h. Fresh-laid eggs did not allow any penetration up to 24 h. Above results corresponded very well with the penetration study with Salmonella enteritidis and also with the morphological study of eggshell surfaces using electron microscopy where fresh-laid eggs had intact cuticle layers, but commercial eggs did not. Thus, Blue Lake dye might be used as a rapid indicator of bacterial penetration through eggshells.     

Ridge, I. (ed) Plants

This book for students new to plant biology emphasizes the functionalside of plant life. Although the topic is large, Irene Ridgeand her five co-writers (Mary Bell, Hilary Denny, Jeremy Roberts,Sue Downs and Phil Parker) have kept the size down to a lengththat is well suited to the study desk rather than the coffeetable. Careful reading of this thoughtfully prepared text byany reasonably diligent student should establish a sound butflexible framework on which to base future years of botanicallearning. The book distils many of the essentials but stillleaves the reader feeling in touch     

Evolutionary transitions in symbioses: dramatic reductions in bathymetric and geographic ranges of Zoanthidea coincide with loss of symbioses with invertebrates

Two fundamental symbiosis‐based trophic types are recognized among Zoanthidea (Cnidaria, Anthozoa): fixed carbon is either obtained directly from zooxanthellae photosymbionts or from environmental sources through feeding with the assistance of host‐invertebrate behaviour and structure. Each trophic type is characteristic of the suborders of Zoanthidea and is associated with substantial distributional asymmetries: suborder Macrocnemina are symbionts of invertebrates and have global geographic and bathymetric distributions and suborder Brachycnemina are hosts of endosymbiotic zooxanthellae and are restricted to tropical photic zones. While exposure to solar radiation could explain the bathymetric asymmetry it does not explain the geographic asymmetry, nor is it clear why evolutionary transitions to the zooxanthellae‐free state have apparently occurred within Macrocnemina but not within Brachycnemina. To better understand the transitions between symbiosis‐based trophic types of Zoanthidea, a concatenated data set of nuclear and mitochondrial nucleotide sequences were used to test hypotheses of monophyly for groups defined by morphology and symbiosis, and to reconstruct the evolutionary transitions of morphological and symbiotic characters. The results indicate that the morphological characters that define Macrocnemina are plesiomorphic and the characters that define its subordinate taxa are homoplasious. Symbioses with invertebrates have ancient and recent transitions with a general pattern of stability in host associations through evolutionary time. The reduction in distribution of Zoanthidea is independent of the evolution of zooxanthellae symbiosis and consistent with hypotheses of the benefits of invertebrate symbioses, indicating that the ability to persist in most habitats may have been lost with the termination of symbioses with invertebrates.     

Factors Controlling the Abundance and Size Distribution of the Phototrophic Ciliate Myrionecta rubra in Open Waters of the North Atlantic

ABSTRACT. Myrionecta rubra, a ubiquitous planktonic ciliate, has received much attention due to its wide distribution, occurrence as a red tide organism, and unusual cryptophyte endosymbiont. Although well studied in coastal waters, M. rubra is poorly examined in the open ocean. In the Irminger Basin, North Atlantic, the abundance of M. rubra was 0–5 cells/ml, which is low compared with that found in coastal areas. Distinct patchiness (100 km) was revealed by geostatistical analysis. Multiple regression indicated there was little relationship between M. rubra abundance and a number of environmental factors, with the exception of temperature and phytoplankton biomass, which influenced abundance in the spring. We also improve on studies that indicate distinct size classes of M. rubra; we statistically recognise four significantly distinct width classes (5–16, 12–23, 18–27, 21–33 μm), which decrease in abundance with increasing size. A multinomial logistic regression revealed the main variable correlated with this size distribution was ambient nitrate concentration. Finally, we propose a hypothesis for the distribution of sizes, involving nutrients, feeding, and dividing of the endosymbiont.     

Technique,Safety, and Efficacy of Intra-Abdominal Transmitters in Nine-Banded Armadillos

ABSTRACT The future management of nine-banded armadillos (Dasypus novemcinctus) requires solid space-use and activity data, which are currently lacking and which radiotelemetry can provide. External radiotransmitters have not been successful applied with this species. To make recommendations for intra-abdominal radiotransmitter placement in nine-banded armadillos, we 1) evaluated 4 different anesthetic protocols for safety, efficiency, and cost-effectiveness; 2) evaluated a surgical technique for the intra-abdominal placement of radiotransmitters that addresses problems described in previous studies; and 3) evaluated the physiologic and behavioral effects of such a technique. We captured and surgically implanted 37 nine-banded armadillos using either butorphanol and isoflurane, ketamine alone, ketamine and xylazine, or a combination of butorphanol, ketamine, and medetomidine for anesthesia. We recovered and necropsied armadillos after the completion of the study. The objective and subjective assessment of butorphanol, ketamine, and medetomidine combination protocol, followed by reversal of the anesthesia with atipamezole, showed that it was the best overall anesthetic protocol for field use, providing both a smooth induction and fast recovery. We evaluated the fate and effects of radiotransmitters on 13 recovered animals at the end of the study and found no adverse effects. We recommend the implantation of radiotransmitters that are allowed to free-float within the abdominal cavity and specifically emphasize the need for strict aseptic technique. Wildlife managers and wildlife veterinarians aiming to implant nine-banded armadillos with radiotransmitters will benefit from using the recommended anesthetic protocol and surgical technique in future studies.     

Direct and indirect effects of nitrogen deposition on species composition change in calcareous grasslands

Atmospheric nitrogen (N) deposition has been identified as a major threat to biodiversity, but field surveys of its effects have rarely focussed on sites which are actively managed to maintain characteristic species. We analysed permanent quadrat data from 106 plots in nature reserves on calcareous grassland sites in the United Kingdom collected during a survey between 1990 and 1993 and compared the data with the results from resurvey of 48 of these plots between 2006 and 2009. N deposition showed no significant spatial association with species richness, species diversity, or the frequency of species adapted to low nutrient conditions in the 1990–1993 dataset. However, temporal analysis showed that N deposition was significantly associated with changes in Shannon diversity and evenness. In plots with high rates of N deposition, there was a decrease in species diversity and evenness, a decline in the frequency of characteristic calcareous grassland species, and a lower number of rare and scarce species. As all sites had active management to maintain a high diversity and characteristic species, our results imply that even focussed management on nature conservation objectives cannot prevent adverse effects of high rates of N deposition. Structural equation modelling was used to compare different causal mechanisms to explain the observed effects. For change in Shannon diversity, direct effects of N deposition were the dominant mechanism and there was an independent effect of change in grazing intensity. In contrast, for change in herb species number, indirect effects on soil acidity, linked to both N and S deposition, were more important than direct effects of N deposition.